61948-ZZ bearing: complete specifications & equivalents
The 61948-ZZ is a ISO 15 radial bearing sized 240 x 320 x 38 mm (bore x OD x width) with ZZ sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NSK |
| Bore diameter d | 240 mm |
| Outer diameter D | 320 mm |
| Width B | 38 mm |
| Material | GCr15 |
| Seal / shield | ZZ |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 170 kN |
| Basic static load rating C0 | 190 kN |
| Mass | 8490 g |
| Manufacturer designation | NSK 6948ZZ |
| Standard | ISO 15 |
| Catalog version | NSK Rolling Bearings E1103 Part C |
| Last verified | 2026-09-24 |
Source: catalog reference (NSK Rolling Bearings E1103 Part C) · extracted 2026-09-24
Dimensions in inches & 61900-series range
| Bore d | 9.449 in |
|---|---|
| Outer diameter D | 12.598 in |
| Width B | 1.496 in |
| ISO bore code | 48 |
| Radial section height (D−d)/2 | 40 mm |
| Smallest bore in 61900-series | 10 mm |
| Largest outer diameter in 61900-series | 420 mm |
| Width range across 61900-series | 6–56 mm |
| Bore position in 61900-series (smallest first) | 34 of 37 |
| Bore above smallest 61900-series size | 230 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61948 | ISO-INTERCHANGE | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | ISO 15 envelope interchange; NSK suffix 6948ZZ maps to industry-neutral ZZ. Verify seal design, grease and speed rating per brand catalogue. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the 61948-ZZ model number is decoded
In the 61900-series (ISO 15 diameter series 9) the last two digits encode the bore: 61948 carries bore code 48 = 240 mm. Outside diameter 320 mm and width 38 mm come from the ISO 15 boundary-dimensions general plan. Suffix -ZZ denotes two non-contact metallic shields; they retain grease and block coarse debris but are not liquid-tight. For normal-load mounting with a rotating inner ring on a 240 mm shaft, typical catalogue practice is a m6 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude.
Typical equipment & failure modes
Common applications
- textile machinery
- packaging machinery
- space-constrained gearboxes
- clutch and transmission assemblies
Known failure patterns
- fine-particle abrasion when non-contact shields let dust past in dirty duty
- grease aging in the shield-for-life cavity with no relubrication path
- rolling-contact fatigue spalling after the rated L10 life is exceeded
- brinelling from static overload or hammering during mounting
Selection pitfalls — read before you substitute
- Mount this 240 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
- The 619xx thin section (40.0 mm section height at 240 mm bore) trades load capacity for compactness; stiff, accurately aligned seats are essential or edge loading will spall the raceway early.
- ZZ shields are non-contact: 61948-ZZ blocks chips and coarse dust but is not waterproof — do not install it expecting a pressure-wash seal, step up to 61948-2RS for that.
- Shielded 61948-ZZ units are typically greased for life; prying the shields out for regreasing usually bends them and leaves a gap that throws grease in service.
- Assign fits by which ring rotates: an interference shaft fit for a rotating inner ring; if the outer ring rotates instead, reverse the logic — a loose rotating ring creeps and frets its seat.
- NSK catalogues the shielded version as 6948ZZ — suffix ZZ, two non-contact steel shields; the industry-neutral page spelling is -ZZ. Quote the NSK designation when ordering.
- The 170/190 kN ratings, mass 8490 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6948ZZ; this seal/size combination has no counterpart in the SKF 17000 extract used elsewhere on this site, so the page rests on a single manufacturer source — internal geometry and ratings legitimately differ between brands, so re-verify before substituting in a rated drive.
Frequently asked questions
What are the dimensions of a 61948-ZZ bearing?
A 61948-ZZ deep-groove ball bearing has a 240 mm bore, 320 mm outer diameter and 38 mm width (9.449 × 12.598 × 1.496 in), per ISO 15 boundary dimensions. It is fitted with two non-contact metallic shields.
How does the 61948 bore code work?
The last two digits of 61948 are bore code 48, giving 48 × 5 = 240 mm bore. The 320 mm outside diameter and 38 mm width follow the ISO 15 diameter series, not the bore code alone.
What does the ZZ suffix on 61948-ZZ mean?
ZZ means two non-contact sheet-metal shields, one each side. They retain factory grease and block coarse particles with little friction, but do not seal against liquids, fine dust or pressure washing.
How does the 61900 compare with other series at the same 240 mm bore?
619 is a thin section one step above 618: 320×38 mm with a 40.0 mm radial section at 240 mm bore; a 6248 on the same bore is substantially larger and more heavily rated.
What is the NSK designation and catalogue data for 61948-ZZ?
In the NSK Rolling Bearings catalogue (E1103 Part C) this size is listed as 6948ZZ — two non-contact steel shields (NSK suffix ZZ), 240×320×38 mm per ISO 15. Quoted values: C 170 kN, C0 190 kN, mass 8490 g. The industry-neutral page spelling 61948-ZZ follows the seal-suffix convention used across this site, not NSK order-number spelling. Reference and limiting speeds are not tabulated in the E1103 dimension tables used here; consult NSK speed tables before high-speed service.
Reviewed & verified by the MPN Base engineering desk against source catalog NSK Rolling Bearings E1103 Part C on 2026-09-24. Read our editorial & correction policy.